Nathan Fillion, who starred in the cult favorite "Firefly" and is currently on ABC's "Castle," will appear Saturday and Sunday at Wizard World Comic Con in Philadelphia.

Nathan Fillion, who starred in the cult favorite "Firefly" and is currently on ABC's "Castle," will appear Saturday and Sunday at Wizard World Comic Con in Philadelphia. (MORNING CALL FILE PHOTO)

Proudly fly your geek flag at Wizard World Comic Con in Philly

If you're a Whovian or a Browncoat, you'll want to head down to Philly this weekend.

The 15th annual Wizard World Comic Con, featuring stars like David Tenant of "Dr. Who" and Nathan Fillion of "Firefly," is at the Pennsylvania Convention Center Thursday, May 7 to Sunday, May 10.

Tenant, who played the 10th doctor, will be on hand for a panel at 10:30 a.m. Saturday. He'll also be available for photo ops and autographs on Saturday and Sunday. Fillion, who stars in ABC's "Castle," will appear Saturday.